The study on energy dissipation of two-jet with varying spacing on a plunge pool based on CFD

Abstract

Unsteady incompressible flowing N-S equation, RNG k - ε turbulence model, and VOF (Volume of Fluid) method have been adopted to numerically simulate the flow structure of two-jet with varying spacing on a plunge pool, with reference to the Xiluodu double curvature arch dam. The variable law of time average flow energy and dissipating rate of two-jet with different spacing shooting into a plunge pool have been computed and analyzed. The results show that for the two-jet into a plunge pool, flow energy is mostly used up at submerged jetting section, the change of jet flow spacing produces a little influence on the time average energy dissipating rate of the upstream flow, whereas, big influence on that of the downstream flow, the smaller jet spacing is, the larger the energy dissipating rate of the downstream flow will be. Therefore, if the flow is discharged from a dam in layers, after satisfying the requirements of fully functioning of hydrodynamic cushion, relatively small jet spacing shall be adopted as it can be to further raise time average energy dissipating rate at submerged jetting section. This study can offer reference to the optimum design of a plunge pool and appreciate layout of a dam outlets.